Internal-combustion engine.



Pafiented 0st. 29, 1912.

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FREDBIOK A. THURSTQH, F EJ553311, MASSACHUSEETS.

nwsmzsh ccmusmcu ENGINE.

Specification of Letters Yatent.

eases-mace eaters.

Application filed September 29, 1908, Serial No. 455335;,

To all whom may concern:

Be it known that 1, Female A. THUPSTON, un, in the county of EssevandState assachusetts, have lIlV'Qhtt :er: .itc new and a fol Improvementsin lncernaL-Cmm hustlou Engines, of which the foll'owm is aspecification.

This invention relates to engines of the type which combustible mixtureis eX- A loded in the cylinder to drive the piston thereof, and hasparticular reference to engloss of that character which operate with atwo-stroke cycle.

The objectof of back-firirzg into the carburetor and to eliminate thenecessity of a check valve in the pipe through which the combus tllolemixture is admitted to the engine. I l-1 lllPllSll these objects loyconstructing the engine with its ports so arranged that the pistoncovers and uncovers them successively at, the roper times to insure oeration of the engine, and so that the port by which the combustiblemixture is first admitted to the engine is covered Wheneveran explosiontakes place. By this means the piston takes the place of valves andrenders the same in any of: the ports unnecessary. Prevention ofback-firing in the carburetor and the pipe by having the exhaust port atthe most remote possible point from the admission porthy providing thatthe port through v71 oh the fresh mixture is admitted to the su ine beclosed whenever the exhaust port and the passage through which themixture is conducted to the combustion chamber are opened. I enabled tohave the exhaust port situated on the opposite side of the engins fromthead'mission port and the passage which conducts the mixture into thecombustion chamber, which is the point of maximum remoteness, by theconstruction which constitutes the present invention, and which ishereinafter described and claimed; U25 the accompanying drawings,Figu1-eeseets internal combustion engine t any invention. Fig. 2 represents andsection on line 22 of Fig. 1. Fig.

Fig. 1. Fig. l represents a cross-section on tunes-4s of Fig. 1. Fig. ,5represents a cross-section on line -5 of Fig". l.

The .sa,me reference characters indicate ssme perts in all the figures.

Referrmgto the drawings, which illusthe invention is to obviateleadingtherefrom to the engine is permitted resents a cross-section on line 3-80ttrate an internal combustion engine Working on the two-stroke cycle, 1represents the cylinder of the engine, and 2 represents the crank case.This crank case formed of two parts, one of which is integral with thecylinder casting", and the other of which is ooltedto the firstpart byloolts 3 having flanges 4 for that purpose. 5 represent the piston, 6the connecting rod, 7 the crank, S the shaft, and 9 the fly wheel of theengine. "lhe crank case and cylinder casting togcther inclose a spacewhich is airtight so that it may contain combustible vapor underpressure withoutdanger of leakage. This space is divided by the pistoninto two chambers off variable volume, one of which is-tlle combustionchamber 10 in the head portion of the cylinder, and the other areceiving chamber ll in the crank ease and crank end of the cylinder.The com ustible mixture of volatile hydrocarbon and air is carried tothe engine from a carlou cter {not shown) through a pipe 12, and isadmitted into the receiving chamber through a port 13 in the wall of thecylinder, which I term the admission port This part is opened when thepiston is at the head end of its stroke, as illustrated in Fig. 2, andis covered by the piston at all other times. Durjing theworking strokeoi the engine tle :gvolume of combustible mixture in the re- Icelvingchamber is compressed. and at the end of this stroke is allowed to intotl e combustion chamber through an inlet or-t 14, which is connectedwith the ad: chamber by passages hereinafter descriln The inlet port 14is located at such a poi in the cylinder wall that it is uncoveredtravel past itof'the piston whenthe reaches the crank end 01? itsstroke, that isv the end of its Working stroke, and is covered by thepiston at all other .times. The exhausted gases are allowed. to escapethrough an exhaust port 15 and a pipe 16 in'the cylinder wall. This portis located nearer the head of the cylinder than is "the inlet port 14:so as to be uncovered by the piston and opened to permit the hot burntgases to escape before the inlet port. is opened to the admission of thefresh mixture.

The passage or passages by which the combustible mixture is conductedfrom the receiving ehamhe to the inlet portl% is a divided or two-branchpassage which entirely surrounds the inlet port This. passage opens intothe combustion chamber admission port 13, the passage ports 21 andpossibly be located. Thereby ,the danger '14:. Thse branches and theinlet 17 of the thick enough to provide space for theusual branches liland 20 of the passage constitute quently the engine may be operatedwholly both sidesof the admission port, it is pos-" at 17 where thecylinder and crank case join, and [extends upward. rat 18 the passagedivides into two branches-19' and 20 which diverge until they areseparated more widely than the width of port 13,then -extend toward thehead of the cylinder in parallel and join together again in the portpassage are contained wholly within the shell pr-wall ofithecylindenwhiclris made ooling water jacket. a I

As' the openings 21 and 22a into the ports,'-itwill be seen that'thisengine contains five ports, thes'being respectively, the

22, the inlet port 14, and the exhaust port 15. -The latter port is onthe opposite side of the cylinder from the first tour ports, and thus,is as far away from them as it can of fire being communicated to theadmission port 13 is reduced to the minimum, for before the pistonceases its travel, the exhaust port is opened and the burning gases canonly reach the admission port bytraveling between the piston andcylinder walls, and it would have the maximum distance to travel so thatdanger of this result taking place is made as slight as possible. Also,since the admission port is so. remotevfrom the exhaust port and thedirect passage from one to the other is closed by the piston, thenecessity of having a check valve in the admission pipe 12 iseliminated' Consewithout valves.

The port 14 is shown asextending entirely through the shell of thecylinder. This construction is adopted for structural reasons wholly, inorder tosimplify the casting of the engine. As far as concerns theoperation of the engine, the port 14 oh its outer side might terminateon the same line with the outer boundaries of the passages. 19 and 20which lead from the passages 19 and 20 to the port 14. By reason ofhaving the passage from the receiving chamber to the inlet port dividedand carried around sible to arrange all these ports on the same side ofthe engine, and at the same time to provide the area requisite to allowthe necessary flow of vapor into the combustion chamber, withoutinterfering with any of the appendages of the engine' I claim receivingchamber.

1. two-stroke cycle engine comprising a copies of tms patent. may beobtained single cylinder, a crank case connected to the cylinder and apiston reciprocating in such cylinder separating the interior thereof.into a combustion chamber and a receiving chamber, the cylinder havingin one of its side walls an exhaust port arranged to be opened when thepiston is at the crank end of its stroke, an inlet port arranged to beopened when the piston is at the head end of the stroke, and a transferpassage cast in the wall of the cylinder wholly in the opposite sidefrom the exhaust port, communicating with the crank case in a singleopen- .ing, branching so as ,to pass around the inlet port and openinginto a port in the cylinder wall which is uncovered so as to communicatewith the combustion chamber when the piston isat the crank end of itsstroke. 1

2. A two-cycle internal combustion engine comprising a single cylinderand apiston arranged to reciprocate therein and to divide its interiorinto a combustion chamber and a receiving chamber; the cylinder beingformed with an exhaust portin one side wall, with two admission ports inthe opposite side wall, one of which admission ports is below the otherand is arranged to admit v a coTnbustible' mixture to the receivlngchamber when the piston is at the head end of the stroke, and with adivided passage formed wholly in the cylinder wall at the side oppositeto the exhaust port, surroundjing the lower admission port and openinginto the outer admismn port and-into the 3. -A two-cycle .1 ternalcombustion engine comprising a siiigle cylinder having a .combustionchamber, a receiving chamber, and a piston separatingsaid rchambers fromeach other, and having an admission port opening into the receivingchamber, a transfer port opening from the receiving chamber and dividinginto two branches contained wholly within the cylinder, Wall at one sideof an axial plane andinclosing the admission' port between them, asecond admission port with which said branches join and so arranged inthe cylinder wallcas to be uncovered when the piston is at the end ofits working stroke, and an exhaust poi-tin the cylinder wallsdiametrically opposite to the zcr fivecents each, by addressing theCommissioner of latents,

Washington, 3). (3.

